The invention relates to a closure, comprising:a cap body (12) formed from a first material, the cap body defining a cavity (24) therethrough；a stopper (30) formed from a second material and disposed within the cavity, the second material being different than the first material； anda barrier layer (40) formed from a third material, the third material being different from at least the first material and associated with at least one of the cap body and/or the stopper, and wherein barrier layer is disposed across at least a portion of the cavity.
